1. Field of the Invention
The present invention relates to a paper machine clothing fabric, and more particularly, to monofilament yarns used in the paper machine clothing fabric.
2. Description of the Related Art
Polyethylene terephthalate (PET) is a polymer having good tensile properties, processability and low moisture absorption. PET is used extensively in apparel, home furnishings and industrial applications. Although PET has been utilized in the paper machine clothing (PMC) industry, due to the hostile conditions of the paper manufacturing process the mechanical life of PMC fabrics formed from PET is limited. During the operation of the papermaking machine the hostile conditions, such as mechanical stress, heat and moisture, work to break PET monofilament yarns down, thus shortening the life of a fabric formed from such yarns.
Although efforts have been made to increase the life of PMC fabrics formed from PET monofilament yarns, each proposed solution to the problem of low abrasion resistance has its disadvantages. For example, one approach to solving the problem of low abrasion resistance of PET monofilament yarns was to use high molecular weight PET, as evidenced by EP 0 158 710 A1. Other efforts have involved the utilization of various additives to improve the physical properties of PET monofilament yarns, such as abrasion resistance. Each of these proposed solutions, however, requires expensive resin, expensive additives, and/or longer processing times which lead to higher production costs.
What is needed in the art is a PMC fabric and, more particularly, a PMC fabric yarn having improved or higher abrasion resistance, which is cost effectively produced without the need for additional additives or expensive resin.